Some rotors of gas turbine engines are characterized as critical rotating components based on a consideration that the rupture of such rotors could be associated with an unacceptable risk that the released high energy rotor fragment(s) would not be contained by the surrounding engine casing. Accordingly, such rotors are designed to minimize the risk of rupture and of high energy fragment release, and thus manufactured from materials meeting relatively stringent mechanical property requirements so as to ensure adequate fatigue and damage tolerance capabilities. However, materials that meet more stringent mechanical properties requirements can be more costly. Moreover, ensuring that released fragments are contained typically requires increasing the thickness of the casing, which adds weight to the engine.